[Hammarlund] [National] National Select-o-Ject Question

[Kenneth G. Gordon]

On 23 Feb 2011 at 13:28, D C *Mac* Macdonald wrote:

> Can anybody provide a comparison of usefulness
> between the Select-o-Ject and a Heathkit Q-Multiplier?

The biggest difference is that the SOJ works at AUDIO, while the "Q-
multipler" works at the IF.

They each have different, but valuable, characteristics.

The SOJ is basically a very narrow, adjustable AUDIO filter.

The "Q-Multiplier" can insert both a very narrow peak in the IF passband, 
and a frequency-adjustable "notch" in the IF passband, but not 
simultaneously.

You can, however, use both the SOJ and the "Q-multiplier" simultaneously.

The handbook published home-built versions of both at various times.

I use both.

Ken Gordon W7EKB